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Switching -frequency -controlled switch -mode power supply unit for powering magnetic resonance system gradient coils

一种开关频率、电源单元的技术，应用在使用核磁共振频谱进行测量、磁共振测量、使用磁变量测量等方向，能够解决需要硬件、难以实现高次谐波充分衰减、梯度线圈功率振幅损失等问题

Inactive Publication Date: 2015-02-25
KONINKLJIJKE PHILIPS NV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this case, it will be difficult to achieve sufficient attenuation of higher harmonics
Filtering too much can result in an excessive loss of gradient coil power amplitude
This is bad as the purpose of the power supply unit is to deliver as much power as possible to the gradient coils
As another disadvantage, the power loss creates power dissipation within the filter, so the filter must be cooled, requiring additional hardware at additional cost

Method used

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  • Switching -frequency -controlled switch -mode power supply unit for powering magnetic resonance system gradient coils
  • Switching -frequency -controlled switch -mode power supply unit for powering magnetic resonance system gradient coils
  • Switching -frequency -controlled switch -mode power supply unit for powering magnetic resonance system gradient coils

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Embodiment Construction

[0038]This specification contains several embodiments of the invention. Various embodiments are described below with reference to a particular set of figures and are identified by a prefix designation of a particular embodiment. Functionally identical or substantially identical features in all embodiments are identified by a reference number consisting of the embodiment-related prefix number plus the feature number.

[0039] figure 1 Shown is a block diagram of a magnetic resonance (MR) examination system 110 comprising an MR scanner 112 and a magnetic gradient system 126 with a power supply unit 130 and gradient coils 128 according to the invention. The MR examination system 110 includes a main magnet 114 that in at least one operating state generally has a static magnetic field strength showing the inevitable loss due to the superconducting main magnet operating in persistent mode and due to variations in Time drift due to environmental conditions. The main magnet 114 has...

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Abstract

A power supply unit (130) for powering at least one gradient coil (128) of a magnetic resonance (MR) examination system (110) with a main magnet (114) having, in at least one state of operation, a substantially static magnetic field strength, and with an MR measurement signal bandwidth, the power supply unit (130) comprising: a switched-mode power converter (134) for powering the at least one gradient coil (128), comprising at least one switching member provided to switch between a conducting state configuration and an essentially non-conducting state configuration at a first fundamental switching frequency (fSW); a pulse control unit (132) designed to provide switching pulses at the first fundamental switching frequency (fSW) for controlling the switching of the at least one switching member; wherein, upon triggering by a trigger signal (142), the pulse control unit (132) is provided to change the first fundamental switching frequency (fSW) to at least a second fundamental switching frequency (fSW).

Description

technical field [0001] The invention relates to a power supply unit for supplying gradient coils of a magnetic resonance (MR) examination system and a method of operating the power supply unit by controlling the switching frequency. Background technique [0002] In the field of Magnetic Resonance Imaging (MRI), it is well known to use switch-mode power converters to power gradient coils of MR examination systems. Switch-mode power converters use pulse width modulation (PWM) with a fixed effective fundamental switching frequency in the range of, for example, 20-100 kHz. For protons (hydrogen nuclei) or other nuclei, higher harmonics of the fixed effective fundamental switching frequency may interfere with the MR measurement signal within the measurement signal bandwidth of MR imaging and / or spectroscopy, thereby degrading the MR measurement signal. Switch-mode power converters are usually equipped with an output filter for each gradient coil axis to achieve adequate attenuat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R33/385
CPCG01R33/3852G01R33/385G01R33/38G01R33/46
Inventor C·L·G·哈姆M·A·霍兰德M·J·A·M·范赫尔沃特M·P·巴克斯
Owner KONINKLJIJKE PHILIPS NV
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